The mode of administration and release kinetics of sustained-release drug formulations can have a profound effect on therapeutic efficacy. The use of polymer materials in this regard is well established and has led to numerous successful methods of both controlling drug release and providing sustained release over days to months, even years. Polymeric drug delivery devices for implantation in vivo have demonstrated durability and biocompatibility. Many of these drug delivery devices which provide sustained release of an agent, however, are inert under biological conditions resulting in the need for surgical resection following complete drug release.
An additional challenge is the difficulty in manufacturing materials with therapeutic agents and particularly maintaining uniformity among micron and sub-micron devices. Microfabrication techniques developed by the semiconductor industry have started to receive attention for developing timed pulsatile drug release systems such as presented in Santini et al. “Microchips as Controlled Drug Delivery Devices” Angew. Chem. Int. Ed. 39, 2396-2407, 2000, which is incorporated by reference herein.
There remains a need for biodegradable implantable drug delivery devices with controlled drug release that can be manufactured to consistent specifications on a micron or sub-micron scale.